Operating circuit for a discharge lamp
US5198728A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 17, 1991 |
| Grant date | Mar 30, 1993 |
| Priority date | — |
| Expiry date | Dec 17, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B41/2882
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A switched mode power supply (SNT) is coupled to a source of d-c energy (U.sub.Batt) and provides electrical energy to a lamp within widely varying limits. The switching conditions of the switched mode power supply are controlled by an operation control circuit (ADD) which has a current sensing resistor, serially connected to the lamp, to provide a lamp current signal, and a voltage divider (R2, R3) connected across the lamp to sense lamp voltage and provide a lamp voltage signal. The lamp current signal and the lamp voltage signal are added, compared in a comparator formed by an operational amplifier (IC2-A), with respect to a reference setting power level, and the output signal from the comparator is coupled back to the switched mode power supply to control the switching rate thereof, based on the instantaneous lamp current and lamp voltage. Excess voltage can be compensated by providing either an active semiconductor switching network (T1, T2, FIG. 3) or a passive semiconductor switch (ZD), which affects the added current-voltage signal applied to the comparator (IC2-A).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.